Furnace-grate bar



Feb. 24. 1925.

H. J. WEBSTER FURNACE GRATE BAR Filed Sept. 23, 1924 idf/THESSA- Patented Feb. 24, 1925.

UNITED STA-'rss PATENT OFFICE..

HOWARD J. WEBSTER', OF PHILADELPHIA, PENNSYLVANIA.

FURNACE- GIRATE BAR.

v Application led September 23, 1924. Serial No. 739,297.

Y To @Zlio/tome? -mafg/concern:I

vand State of Pennsylvania, have invented certain new and useful ImprovementsA in Furnace-Grate Bars, of Which the following 'Will tend to preserve a uniform thickness Y is a specification.

.This invention relates to grate bars for and used in conjunction with fuel chambers of furnaces, and more especially steam boiler furnaces, and is an improvement of the invention broadly claimed inl my former ;U. S. Patent, No, 1,464,190, dated August The objects of the invention are: First, to construct a gratebar which is particularly adapted for burning smaller sizes of anthracite and other low grade fuel at a high rate of combustion.

Secondfto so construct and arrange a series of slits Within recesses between grids formed in the upper surface of the grate bar asto produce and deliver a series of separated fan-shaped jets of air through the fuel bed which do not in any Way 'elevate a low grade fuel above. said bed kand supply the requisite amount of air for a high rate of combustion. Y 1 Third, to so construct and arrange the recesses or depressions in the upper grate bar surface and the slits Within the recesses as to not only give the fan-shaped air de- A livery jets a greater distance to spread before meeting the fuel bed 'but at the same time the ash pockets formed by said recesses properly protect the upper vsurface of the grate bar adjacent the highly heated fuel supported by said grate bar.y

Fourth, to lconstruct and dispose the recesses inthe upper surface of the grate bar and arrange the slits in said recesses so.

that theA action of a slicing bar or other furnace firing device upon the fuel Will not force, pack or embed the fine dust of the fuel or ashes into said slits or recesses, thereby destroying the proper combustion of the fuel andeificient operation ofthe furnace.

Fifth, to 'so construct-and arrange the elements comprising thev gratebar, in order to eliminate the commonly usedV pin hole nozzle arrangement and consequent diverg-V ing projected jet action of the air through fuel to be' elevated far above the fuel bed j level and into the combustion space and forming a series of geysers until finally sections` of the fuel bed burn into holes Without fuel, thereby destroying the uniform, maximum and eficient combustion of said fuel for a given area of grate surface.

Sixth, to construct a grate bar which of fuel bed throughout the grate area, and at the same time a constant air pressure in the ash pit, and said air pressure being only v varied to change or control the rate of comgrids is provided on its underside With a depending rib adapted to convey the heat i from the fire surface o-f each grid down to the cooler air space in the ash pit of the furnace, thereby preventing the grids or rate bars from becoming overheated.

Eighth, to construct and arrange a series of connected grids forming the upper or fire surface of a grate bar so that each of said grids is provided on its upper surface with a plurality of specially disposed and arranged longitudinal depressions which cooperate With a herring-bone rib on the underside of each grid to permit the lire surface of the grate or the top or tie-section of each rib formed by the fire surface of the grid to readily bend and adapt itself to the expansion and contraction of the her.-

ring-bone ribs. Y

Ninth, to connect the herring-bone ribs of the end sections or grids of the grate bar t0 the transverse flange ends of the grate bar so that the end ribs Will not burn out should the' same become buried in ashes and deprived of. air circulation and the intense heat above-the grid is transmitted to said endsections.v

Tenth, other objects and advantages'of the invention Will appear from the detailed construction and arrangement of parts and mode of operation to be hereinafter given.

The invention consists of structural char- "acteristics andv lrelative arrangement of eleticularly pointed out in the appended claims.

In the drawing, in which similar reference characters indicate the same parts 1n the several figures: v

j Figure 1 is a ktop plan vievvV of a furnace and partly broken away With `tWo of the improved grate bars in position.

Figure 2 is a longitudinal vertical section on line II--II of Figure 1.

Figure 3 is an enlarged end vieW of one of the grate bars, and

Figure 4t is an enlarged sectional .view taken on the line lV-IV of Figure 1.

Referring to the drawings, and 1-1 are respectively the front and rear wallsof a fuel chamber provided withthe usual grate bar supports 12 and 13, coininonly used in connection with this class of devices and forni no part of the present invention.

14 is one of the seriesof grate bars sustained on said supports 12 and 13 and having the upper or lire surface section 15 and the longitudinal ribs 16 for strengthening and stiifening said bar 14, said ribs 16 being cut away at'their outer and un'der edges to form ledges 161 adapted to rest on said supports 1 2 and 13.

The upper or fire surface section 15 of the gratebar is sub-divided into a plurality or a .series of .grids 17 separated by elongated narrow depressions or recesses 18 Which are preferably arranged transversely of the longitudinal axis ofsaid grate bar 111,and eX- tend to Within short distance of the upper edges of the sides 19, 19, as shown in Figure 1. Said recesses or depressions 18 are also 'preferably semi-circular in cross-section in a longitudinal plane normal to the upper lire surface 15 and rounded at their ends 20, as illustrated in Figure 1.

Each of said depressions or recesses 18 in the grids 17 `is provided with a slotor elongated opening 21 extendingtransversely and entirely across the upper or iire surface section 15 fromone side. 19 to the other side 19, and from the bottom of each of said depressions or recesses 1S to and through the underside surface or face 22 ofthe grids 17 or upper lire .surface section'15as shown in Figure 4, for purposes to be vhereinafter described.

The middle Y}L)ortions;23 ofthe sides 19, 19 of the grate bar are slightly enlarged `or bulgedout, as shown in Figures 3 and et for properly spacing adjacent grate. bars With respect to Veach other and forming a narrow air space between the sides 19 and ribs 16 of the bars.

The upper Aface of each grid 17 lor the upper lire surface section 151s formed Wi th a plurality, preferably three, a middle and ,tivo side longitudinal vdepressions 24, V2i, which are arranged normal to the depressions or recesses y18, 18. as clearly shovvn in Figure land extend through and between the front and rear ends vof the grate-bar for vpurlfioses `to be presently disclosed. 0n the undersurzface 22 of each grid 17 and interposed between the `lowery openings` of the slits 21 is a depending rib or web 25,

preferably of the herring-bone type, said ribs or ivebs connect the longitudinal ribs 16 with each other, as clearly shoivn in Figures 1` and-2, and have the function and are Aparticularly adapted to convey the heat from the upper or fire surface 15 of said grid down tothe cooler air space in the ash pit and prevent the grids 17 or grate bar 14- froin becoming overheated, thereby preventing sagging and burning out, said vdepending ribs or Webs 25 are herring-bone in shape andarrangement forthe purpose-that said ribs 25 mayhave, in View of the disposition of the longitudinal depressions 24, 24 with respectitosaid herring-bone ribs 25, three points of flexure due to a reduction of the T-shaped cross section Wherethe longitudinal depressions 24,2% cut theugrids 17 above the herring-bone ribs 25, and hence permits the ribs or Webs 25`toslightly flex tot-alie up theexpansion or contraction and hence prevent their cracking.

Furthermore an additional function of said ribs 25, 25 is manifestin thatthe `ribs support the top of the grids and rmake them stronger to prevent sagging or resistbloivs from `tiring tools in case it is required to use force to detach or remove clinker formation fused to the grate bar.

The herring-bone ribs of the tivo end gridsof eachgrate bar A 174 is preferably connected to the transverse flanged ends by means of a central longitudinal supporting rib 26 or 27, which rib prevents the end transverse rib fromburning out for reasons previously explained, and gives an additional support for the 4fire surface section 15 of the tivo end grid sections 17, as will be readilyY understood and needs no further disclosure.

The parts `being constructed and arranged as shown ivith a bed of fuel resting on the upper or lire surface section`15, when a draft of airis passing 'from the ash pit and upward through the slits 21 in the grate bar, said air issues from theslits and is delivered in fanshaped iets through the fuel bed Without disturbing or raising the louT grade or iine fuel from the grate bar, and at the same time insuring a properand uniform supply of oxygen over the entire 4grate fora high and quick rate of coinbiistion,thereby effecting a greater'capacity or 'horsepower per square foot o f grate surface than with grate 'bars in which the airis fed through circular openings or pin hole nozzles.

As previously explained, the herring-bone ribs of Webs l25, vr25 most eicien-tly vkeep down the temperature of the entireiire surface of the grate bars so that. Vlong Alife and eiiicient operation of the vgrate is effected and assured under all conditions of service and permits an intensive firing of the'furnace for a short period at lthe peak of the load,lor when it is necessaryto briefly overbar or other firing tool is applied to the fuel bed, said bar will necessarily be required to rest on the upper surface of the grate bar and will thereby be prevented from forcing, packing or embedding the fine fuel-or ashes into the slits 2l or recesses 18, thereby insuring a constant and uniformfeed vof'air and combustion of fuel at all times throughout the entire area of the grate'surface.

From the foregoing description of the `construction and arrangement of parts and inode of operation, 1t Will be readily seenthat a grate bar has been devised lWhich comprises a minimum number of highly efiicient cooperating ele-ments of simple construction, Which can be cheaply manufactured and readily installed or assembledor disassembled or renewedat a minimum of expense and without the use of skilled labor or special tools.

It will also be seen that all the objects and advantages recited in the statement of `invention have been fully carried out, and

While the preferred form has been shown and described, it is to be understood that many changes will suggest themselves Without in any Way changing the material features of construction or departing from the spirit of the invention as expressed in the claims.

'Vhat I claim is: K

l. A furnace grate bar having a fire surface section provided With a series of separated transverse depressions or recesses in its upper face, a continuous slit in each of and extending the entire length of the depressions or recesses of the fire surface section and extending through the under face of the fire surface section, and a plurality of separated longitudinal depressions in said lire surface section and extending across said transverse depressions or recesses.

A furnace grate bar having a fire surface section provided with a series of separated transverse elongated depressions or recesses in its upper face, a slit in each of the depressions or recesses of the tire surface section and extending from the bottom of the depressions or recesses through the under face of the tire surface section, and a plurality of separated longitudinal depressions in said fire surface section and extending across said transverse depressions or recesses.

A furnace grate bar having a horizontal lire surface section in its upper faceprovided with a series of grids separated by elongated and narrow transverse depressions or recesses, a slit in the bottom of each of the depressions or recesses of the fire surface section and extending from the bottom of the depressions or recesses through the under face of the fire surface section, and a plurality of separate longitudinal depressions in said fire surface section and extending across said transverse depressions.`

4. A furnacek grate bar having a horizontal fire surface section in its upper face provided with a series of grids separated by elongated depressions or recesses in its upper face and arranged transversely to the longitudinal axis of the grate bar, and a slit in the bottom of each of the depressions y or recesses of the tire surface section and extending from the bottom of the depressions or recesses through the under face of*v the fire surface section, and a plurality of separated depressions 1n said fire surface and extending across said transverse depressions and full length of the grid bar.

5. A furnace grate bar having a horizontal fire surface section in its upper face provided Wit-h a series of grids separated byl transverse elongated depressions or recesses semi-circular in cross section, a slit in and substantially the entire length vof each of the depressions or recesses and extending from the bottom of the depressions or recesses through the under face of the fire surface section, and a plurality of separated longitudinal depressions in said lire surface section'and extending across said ytransverse depressions or recesses. n

6. A furnace grate bar having a horizont-al iire surface sectionF in its upper face provided with a series of grids separated by transverse elongated depressions or recesses semi-circular in cross section in a4 plane passing through the longitudinal axis of the grate bar, a slit in and substantially the entire length of each of the depressions or recesses and extending from the bottom. of the depressions or recesses through the under face of the fire surface section, and a plurality of separated longitudinal depressions in said fire surface section and extendllO ing across said transverse depressions or recesses.

7 A furnace grate bar having a horizontal ir'e surface section in its upper face provided With a series of grids separated by transverse elongated depressions or recesses arranged transversely to the longitudinal axis of the grate bar and extending to near the side edges of said bar, a slit in the bottom ofeach of the depressions or recesses and extending fromI the bottom of the depressions or recesses through the under face of the fire surface section, and a plurality of separated longitudinal depressions in said fire surface section and extending across said transverse depressions or recesses.

8. A furnace grate bar having a horizontal tire surface sectionin its upper face having aspacing projection on each of its sides and-provided with a series of grids separated by transverse elongated depressions or recesses, and a slit ineach o-f 'the depressions .for recesses of the fire surface-section 4and ,extending from the bottom ofthe depressions -or recesses through the under face of the fire surface section, anda plurality of separated longitudinal depressionsin said fire surface sec-tion and extending vacross saidtransverse depressions or recesses.

9. A furnace grate bar .having a viire surface section in vits upper face provided with .a seriesof ygrids separated by transverse depressions or recesses, a slit in Aeach of the .depressions or recesses of the fire surface section and extending across the upper face and through the under face of `the yfire surface section, and a 'heat-conveying rib `transversely ,arrangedv and depending from the under surface lof eachv of said `grids andin- Aterposed between the slits separating the grids.

10. A' furnace .grate bar having :a irefsur- Vface section in its upper xface provided wit-h a series of grids separated by transverse elongated depressions .or recesses, a slit in each of the depressions `or recesses fof the `fire .surface section and extending across Vthe upper face of .the `tire surface section and from the bottom .of the depressions or .recesses through the under face ofthe fire surface section, and a vheat-wnveying rib herring-bone in shape transversely-arranged and depending from the under surface of each .of said grids and interposed between the slits separating the grids.

yl1. A furnace grate bar having 'a horizontal fire surface section in its upper face lprovided with a series of grids separated by transverse elongated and narrow depressions or recesses, a slit in the bottom of each of the depressions or recesses of the fire surface ,section land extending :across the upper face of the iiresurface section and from .thev

between the `slits separating said grids, and Y' la plurality of separated longitudinal depressions in said fire surface section and extending across said transverse depressions or recesses.

12. A furnace grate bar having a hori- Zontal `tire, surface section in its upper face provided with a series of `grids separated by 1elongated depressions or recesses arranged `transversely to the longitudinal Vaxis of the lg1'ateba r, a slit inthe bottom of each of the .depressions or recesses of the fire surface sectiona'nd extending across the upper face of the fire surface section and from the bot- `tornof ythe depressions or recesses through .the vunder face of the fire surface section, a heat-conveying rib herring-bone in shape transversely arranged and depending from -thfe under surface of each of said grids and interposed between the slits separating said grids, and a plurality of separated longitu- .dinal depressions in said fire surface section :and extending across said transverse depressions or recesses.

In testimony whereof I hereunto amx my f signature.

HOXARD J. EBSTER. 

